• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2007.11a
• /
• pp.1425-1429
• /
• 2007

Consumer's product selection measures are being shifted from the units' operational performance to overall performance. Low noise, low vibration, and low power consumption rate, etc. which used to be additional quality indices, now become vital performance factors. Especially, noise and vibration characteristics are being considered as equivalent to/or even more critical than operational performance in certain products such as office machines and home entertainment systems, which share the same space with human being's daily life. Therefore, noise reduction and sound quality improvement technology becomes an inevitable design issue for those applications. Qualitative noise characteristics of rotating polygonal disk applied to digital printer systems are presented. Overall sound pressure level change and tonal noise variation with respect to the geometrical properties of polygonal disk, operational speed, and others are briefly discussed based on experimental results.

• 한국HCI학회:학술대회논문집
• /
• 2009.02a
• /
• pp.214-220
• /
• 2009

Recent advanced technologies enable multiple users to share the virtual environment and work together as they are collocated. Additional sensory information such as haptic could improve the cooperation. In this paper, we propose a server-client architecture with multi-rate haptic control to support a tangible cooperation. Using our approach, the system is able to maintain a consistent simulation state across multiple users as well as to provide a highfidelity stable haptic interaction. To verify our approach, we have developed an experimental application and tested the cooperation among multiple users. The results confirm that our system is able to provide coherency among clients as well as haptic transparency.

• Journal of Korea Multimedia Society
• /
• v.8 no.12
• /
• pp.1597-1604
• /
• 2005

Recursive Patching is an efficient multicast technique for large-scale video on demand systems and recursively shares existing video streams with asynchronous clients. When Recursive Patching initiates a transition stream, it always makes a transition stream have additional data for the worst future request. In order to share a VOD server's limited network bandwidth efficiently, this paper proposes Practical Patching that removes the unnecessary data included in the transition stream. The proposed Practical Patching dynamically expands ongoing transition streams when a new request actually arrives at the server. As a result, the transition streams never have unnecessary data. Simulation result confirmed that the proposed technique is better than Recursive Patching in terms of service latency and defection rate.

• MALSORI
• /
• no.33_34
• /
• pp.43-55
• /
• 1997

This study examined one of the hypotheses on the consonant reduction in Korean inferred from the Articulatory Phonology framework through phonetic experiments: Degree of consonant reduction depends on the height of the neighboring vowels--the lower the height of the neighboring vowel is, the higher the degree of reduction of stop closure period is. The results of this study, in general, turned out to support the hypothesis with some cases requiring other phonetic considerations, e.g., rate of some tongue tip movement in the case of dental lenis stop /t/ or the facts that bilabial lenis stop /p/ share its primary articulators, lips, with the neighboring vowel /u/ and that for bilabial closure, the upper lip lowers more for compensation of little movement of lower lip when its raising gets disturbed for some reasons.

• Journal of the Korean Operations Research and Management Science Society
• /
• v.34 no.4
• /
• pp.1-14
• /
• 2009

This study empirically tests post-M&A performance through competitiveness variables based on extensive firm-based panel data over the past 26 years in the world steel industry. Different measures of profitability, productivity, efficiency, market share, and growth rate which are considered as critical factors of competitiveness are used in the analysis. In particular, this paper tries to separate M&A samples into two cases; horizontal integration (between steel makers) and vertical integration (between steel makers and iron ore suppliers/steel consuming firms). Merged firms show significant improvement in competitiveness relative to other individual firms in the steel industry.

• Journal of the Korean Operations Research and Management Science Society
• /
• v.26 no.1
• /
• pp.61-69
• /
• 2001

This paper presents a two stage game model which examines the effect of learning-by-doing and spillover. Increases in the firm’s cumulative experience lower its unit cost in future period. However, the firm’s rival also enjoys the experience via spillover. Unlike previous theoretical research model, a cost asymmetric market entry game model is developed between the incumbent firm and new entrant. Mathematical results show that the incumbent firm exploits the learning curve to gain future cost advantage, and that the diffusion of learning to the new entrant induces the incumbent firm to choose decreasing output strategically. As a main result, we show that the relative magnitude between the learning and spillover rate determines the market share ratio of competing firms.

• Knowledge Management Research
• /
• v.12 no.5
• /
• pp.1-10
• /
• 2011

Forming a network, through Social Network Services (SNS), among a group of people who share the same hobby or interests could increase the information sharing among the members at an exponential rate. Moreover, SNS users' behavior extends beyond the traditional introverted consumption behavior to a proactive behavior by owning or actively sharing product information. For firms, such proactive consumer behavior translates into marketing effects such as the word of mouth (WOM) effect. Therefore, SNSs are accepted not only as a communications channel between firms and consumers but also as marketing channel, suggesting the possibility of a new revenue source. In this context, we will explore into the factors of SNS contents which conserve firms' image and product information, and effects of the factors on consumer attitude and WOM.

• Journal of Nutrition and Health
• /
• v.38 no.9
• /
• pp.786-792
• /
• 2005

With dramatic transitions from a traditionally food-insecure to a food-sufficient society, over weight and/or obesity are an increasing health concern in Korea. In 2000, $35.9\%$ of Korean adults were over weight (BMI>25) with increasing trends. It is well known that obesity is highly correlated with chronic diseases, such as diabetes, hypertension, cardiovascular disease, cancer and high cholesterol. In 2003, the social cost of obesity is estimated at $529.5\~799.3$ billion won (direct cost) and at $1,200\~1,817$ billion won (including indirect cost). The share of the direct cost is estimated at $2.6\~3.9\%$ of total medical bill 20,742 billion won. These costs are underestimated and would surely be higher if the expenditures outside of the official medical insurance system of Korea were included. Based on the rapid increase of obesity rate among the Korean youth, it is crucial to develop and implement appropriate policies to curb the obesity epidemic.

• Journal of Integrative Natural Science
• /
• v.13 no.3
• /
• pp.105-113
• /
• 2020

As the COVID-19 outbreak has prolonged, social distancing movements are encouraged and non-face-to-face lifestyle trends are spreading. As a result, it is necessary for general restaurants and small marts to provide delivery services like large-scale distribution companies. Large distribution companies have also suffered significant economic losses from COVID-19 because epidemiological investigations were conducted after the distribution center was closed due to the outbreak of COVID-19 in several large domestic distribution companies. In this thesis, in order to examine whether COVID-19 actually affects distribution companies, we attempt to understand the relationship between the number of confirmed cases per month and the sales share and growth rate by categories of distribution companies.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.7 no.1
• /
• pp.1-10
• /
• 2007

In recent few years, low-power electronics has been a leading drive for technology developments nourished by rapidly growing market share. Mobile DRAM, as a fundamental block of hand-held devices, is now becoming a product developed by limitless competition. To support application specific mobile features, various new power-reduction schemes have been proposed and adopted by standardization. Tightened power budget in battery-operated systems makes conventional schemes not acceptable and increases difficulty of the circuit design. The mobile DRAM has successfully moved down to 1.5V era, and now it is about to move to 1.2V. Further voltage scaling, however, presents critical problems which must be overcome. This paper reviews critical issues in mobile DRAM design and various circuit schemes to solve the problems. Focused on analog circuits, bitline sensing, IO line sensing, refresh-related schemes, DC bias generation, and schemes for higher data rate are covered.